Cleanup sandcastle and docs for ground atmosphere

[OmarShehata]

What I did

I think the current Sandcastle names of "Atmosphere" and "Atmosphere color" are confusing, because it implies they're different aspects of the same thing. But "Atmosphere color" only changes the color of the sky as seen from the ground or the atmosphere around the ellipsoid. Whereas "Atmosphere" is specifically about the ground atmosphere.

I renamed them to "Ground Atmosphere" and "Sky Atmosphere" respectively. Both will show up when a user searches for "Atmosphere" so it will be obvious there are two different ways of affecting the atmosphere.

I also updated some things that were copied from the Sky Atmosphere example to the Ground one, and added links to the Sandcastle in the docs.

One problem left

I updated the showGroundAtmosphere doc to say that it's only visible when the camera is at a distance between lightingFadeOutDistance and lightingFadeInDistance but the doc for those say:

The distance where everything becomes lit. This only takes effect when enableLighting is true.

Which seems to contradict this, since you can see it does affect the ground atmosphere whether or not lighting is enabled:

https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/?src=Atmosphere.html

So I'm not sure whether this is expected behavior that lightingFadeInDistance controls both lighting and ground atmosphere and if the doc just needs to be updated, or if there's supposed to be a separate control for ground atmosphere?

@bagnell @lilleyse

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[lilleyse]

So I'm not sure whether this is expected behavior that lightingFadeInDistance controls both lighting and ground atmosphere and if the doc just needs to be updated, or if there's supposed to be a separate control for ground atmosphere?

I think it's expected that it controls both, and the doc just needs to be updated to say it takes effect when enableLighting or showGroundAtmosphere are true.

[lilleyse]

on Sandcastle to in Sancastle?

[lilleyse]

The renames makes sense to me. Just mention them in CHANGES.md (1.50 had a rename too).

[mramato]

Sandcastle examples do not qualify as breaking changes, they are completely outside of the API.

[lilleyse]

Hmm that's true... @OmarShehata could you remove the similar breaking change note from 1.50?

[OmarShehata]

@lilleyse I removed the Sandcastle renames from breaking changes, both for this and for the 1.50 release from CHANGES.md.

[OmarShehata]

@lilleyse this should be good to merge.

[lilleyse]

Ah thanks for the reminder!